Any good tech will be up front about their charges. There's usually an hourly rate and a minimum charge (or 'bench charge'). Some parts can be difficult to obtain but are usually a fraction of the labor cost.

An estimate is what you're seeking. The problem is, 'To find the problem is to fix the problem', for the most part. And sometimes the tech is stumped. So a good approach is for the tech to let you know if it's going to be over a certain $ amount to repair. But they won't know until they've opened it, checked voltage levels, etc. (hence the 'bench charge'). One really can't give a good estimate without checking it out first. So maybe, 'How much to check it out?'.